JP2009237298A - Lighting device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device for efficiently performing uniform irradiation from an annular light-emitting surface having a wide area, and to provide an imaging apparatus. <P>SOLUTION: In a camera 1a having the lighting device having a flash light emitting part and an annular light guide member 10a for converting the light-emitting area of light from the flash light emitting part 4 into an annular area and a photographic lens barrel 3 storing a photographic lens 3a, the annular light guide member 10a has a plurality of annular light guides 14b which are concentrically arranged around the photographic lens barrel 3 and guide the light from the flash light emitting part 4 along concentric circles respectively and grooves 14c which are arranged concentrically with the plurality of light guides 14b to separate the light guides 14b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination device and an imaging device.

Conventionally, as an optical system that converts the light from the flash light emitting unit into illumination suitable for close-up photography (macro mode), the optical path is projected in close-up photography without disturbing the optical path in the normal state, and is arranged around the taking lens. Some guide the light guide (see, for example, Patent Document 1). There is also known an adapter that uses an LED as a light source and converts light emitted from the LED into an annular light emitting portion disposed around a lens barrel portion (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 08-043887 JP 2005-258011 A

  However, Patent Document 1 cannot efficiently guide the light from the flash light emitting portion to the light guide, and there are many components that cause the light to escape from a portion that is not the exit surface. In particular, this tendency was strong when the width of the light guide portion was wide. On the other hand, in Patent Document 2, it has been difficult for the annular light emitting portion that narrows the width of the light guide portion and places importance on efficiency to sufficiently soften the shadow that can be formed in the background due to the reduced light emitting area.

  An object of the present invention is to provide an illuminating device and an imaging device that can efficiently perform uniform irradiation from an annular exit surface having a large area.

  An imaging apparatus according to an aspect of the present invention includes a lighting device including a flash light emitting unit, an annular light guide member that converts a light emission region from the flash light emitting unit into an annular region, and a photographing lens. A photographing lens barrel for storing the annular light guide member, and the annular light guide member is disposed concentrically around the photographing lens barrel, each of which emits light from the flash light emitting portion along the concentric circle. And a plurality of light guide portions having an annular shape, and grooves arranged concentrically with the plurality of light guide portions and separating the plurality of light guide portions.

  An illumination device according to one aspect of the present invention includes a light source and an annular light guide member that converts a light emission region from the light source into an annular region, and the annular light guide member includes concentric circles. And a plurality of light guides each guiding the light from the light source along the concentric circles, and a plurality of light guides arranged concentrically with the plurality of light guides and separating the light guides And a groove.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device and imaging device which can perform uniform irradiation efficiently from the annular | circular shaped exit surface of a large area can be provided.

  Hereinafter, a digital compact camera (imaging device) according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  1 to 9 show a compact digital camera (imaging device) 1a according to the first embodiment. In addition, the camera which can mount the illuminating device of a present Example is not limited to the camera 1a shown in FIGS. 1-3, Other cameras (Single-lens reflex camera, a video camera, etc.) may be sufficient. 1 and 2 are front views of the camera 1a, and FIG. 3 is a perspective view of the camera 1a. The camera 1a includes a camera body 2, a photographing lens barrel unit 3, a flash light emitting unit 4, a release button 5, a viewing window 6 of a photometric device that measures the brightness of external light, a viewing window 7 of a viewfinder, and an annular light guide member. 10a and a reflecting plate 25 (not shown in FIGS. 1 and 2).

  The camera body 2 has a housing structure. The photographic lens barrel 3 accommodates the photographic lens 3a, is provided at substantially the center of the front surface 2a of the camera body 2, and is provided so as to protrude from the front surface 2a. The flash light emitting unit 4 is provided on the upper right side toward the front surface 2a of the camera body 2, and has a narrow rectangular shape in FIGS.

  The flash light emitting unit (light source) 4 constitutes an illumination device together with the annular light guide member 10a.

  The flash light emitting unit 4 includes a flash discharge tube, an internal reflecting mirror, a light guide, and a panel (not shown). The flash discharge tube emits flash as light source means and has a cylindrical shape. The flash discharge tube is disposed so that the longitudinal direction thereof coincides with the horizontal direction in which the flash light emitting section 4 of FIG. 1 extends. The inner surface reflecting mirror has a curvature in a one-dimensional direction that collects and reflects a light beam emitted from the flash discharge tube other than the front, for example, rearward (in a direction opposite to the subject side) to the subject side. The light guide is an optical member that collects the light beam directly incident from the flash discharge tube and the light beam reflected by the internal reflecting mirror and efficiently irradiates the subject side. The panel is a transparent member made of glass or resin having a high transmittance exposed on the front surface 2a of the camera body 2.

  The annular light guide member 10a is provided around the photographing lens barrel 3 on the front surface 2a of the camera body 2, and is used for close-up photography (macro photography). The annular light guide member 10a converts the light emission region from the flash light emitting unit 4 into an annular region (an emission surface 14a described later). The annular light guide member 10 a includes an annular part 11 having a notched annular (ring) shape, and a light receiving part 15 attached to the notch 13 of the annular part 11. The annular light guide member 10a is an optical member formed of a transparent body, and is integrally molded with an optical organic polymer material having high transmittance such as polymethyl methacrylate (PMMA) as shown in FIG. For this reason, the present invention does not employ a method in which the annular portion 11 and the light receiving portion 15 are separately formed and both are joined at the notch 13. The surface on the front side (subject side) of the light receiving unit 15 and the surface on the front side (subject side) of the annular portion 11 are flat (same) with the same height. On the other hand, a groove 14c is formed on the back side (camera body side) of the annular portion 11 as described later, but no groove is formed on the back side (camera body side) of the light receiving portion 15 and the light receiving portion 15 is formed. Is configured as a flat plate member.

  FIG. 4 is an exploded perspective view of the annular light guide member 10a, and the light receiving portion 15 is omitted. FIG. 5 is a partial sectional view or a side view of the notch 13 when the annular portion 11 of the annular light guide member 10a is cut in the radial direction.

  Further, as shown in FIG. 4, a reflective plate 25 having an annular shape is disposed between the annular light guide member 10 a and the front surface 2 a of the camera body 2. The reflection plate 25 may be formed integrally with the front surface 2a of the camera body 2 by performing a treatment for reflecting a part of the exterior member of the camera 1a, or may reflect a part of the metal exterior. It may be used as a surface. With this configuration, a limited space can be used effectively and the manufacturing cost can be reduced.

  As shown in FIG. 4, the annular portion 11 includes a cylindrical or disc-shaped hollow portion 12 and a triangular notch 13. As shown in FIGS. 1 to 3, the photographing lens barrel 3 is inserted into the hollow portion 12 of the annular portion 11, and the light receiving portion 15 is connected to the notch 13.

  As shown in FIG. 5, the annular portion 11 has an emission surface 14a, a plurality (five in this embodiment) of light guide portions 14b, grooves 14c, a back surface 14d, and side surfaces 14e. The emission surface 14a is a plane on which light guided from the flash light emitting unit 4 is emitted. The plurality of light guide portions 14b are concentrically arranged around the photographing lens barrel portion 3, and each guides light from the flash light emitting portion 4 along the concentric circles by total internal reflection, and has an annular shape. The groove 14c separates the light guide portion 14b. The light guide part 14 b and the groove 14 c are formed concentrically with respect to the center of the hollow part 12. The reflection plate 25 has a function of reflecting the light beam emitted to the opposite side of the emission surface 14a of the annular light guide member 10a and returning it to the annular light guide member 10a again, and is the same as the outermost diameter of the annular portion 11. Or it has the outermost diameter beyond it. The diameter of the hollow part 26 of the reflecting plate 25 is the same as the diameter of the hollow part 12 of the annular part 11, and the photographing lens barrel part 3 is inserted into the hollow part 26. The back surface 14d is configured by a plane or a curved surface inclined in the optical axis direction of the photographing lens 3a. Although the side surface 14e may be configured as a reflective surface, in the present embodiment, it is configured as a transmission surface.

  The light receiving unit 15 is the same or slightly larger than the flash light emitting unit 4 and can cover the flash light emitting unit 4, and a light guide unit that guides the light incident on the light receiving end 16 to the annular part 11. 17. The light guide unit 17 includes reflection surfaces 17a and 17b and transmission surfaces 17c and 17d. The reflective surface 17 a is provided between the light receiving end 16 and the annular portion 11 on the left side of the light receiving end 16, and the reflective surface 17 b is formed between the light receiving end 16 and the annular portion 11 below the light receiving end 16. It is provided in between. These reflecting surfaces 17 a and 17 b have a function of preventing light from the flash light emitting unit 4 from leaking to the outside and reflecting such light to the annular part 11. The transmission surfaces 17 c and 17 d are connection surfaces between the light receiving unit 15 and the annular portion 11, and are interfaces that supply light from the flash light emitting unit 4 to the annular portion 11. In the present embodiment, the cross sections of the transmission surfaces 17c and 17d are rectangular.

  The annular light guide member 10a is attached to the camera body 2 so as to be rotatable and movable by the rotation mechanism 30 around the barrel between the first position shown in FIG. 1 and the second position shown in FIG. Is provided. FIG. 1 conceptually shows the rotation mechanism 30 with a dotted line, but it is actually provided inside the camera body 2 and cannot be seen from the outside as shown in FIG. The rotation mechanism 30 may automatically rotate the annular light guide member 10a when the user presses a button (not shown) provided on the camera body 2, or the user manually rotates the annular light guide member 10a. May be. The structure of the rotation mechanism 30 is not particularly limited.

  The first position is a position used for close-up photography (macro photography), and is a position where the light receiving end 16 of the light receiving part 15 of the annular light guide member 10 a covers the flash light emitting part 4. With this arrangement, the light beam emitted from the flash light emitting unit 4 can be guided to the annular light guide member 10a.

  Hereinafter, close-up imaging using the first position will be described.

  FIG. 6 is a block diagram of a control system necessary for the mode switching operation of the camera 1a. As shown in FIG. 6, the camera 1 a includes a CPU (central processing unit or control unit) 40, a mode switch 42, a photometric device 44, an image sensor 46 such as a CCD, and a light emission control circuit 48. The light emission control circuit 48 and the flash light emitting unit 4 are connected by a trigger lead wire 49.

  The operation mode of the camera 1 a is set to the “close-up shooting mode” by the mode switch 42. As shown in FIG. 1, the light receiving end portion 16 of the light receiving portion 15 of the annular light guide member 10 a is rotated by a rotating mechanism 30 to a position covering the front side of the flash light emitting portion 4. In addition, you may rotate the annular light guide member 10a by manual operation, and may be in the state shown in FIG. Further, depending on the setting of the “close-up shooting mode”, the shooting lens barrel unit 3 places the shooting lens 3a in a macro mode position suitable for close-up shooting. The CPU 40 determines whether or not the flash button 4 is caused to emit light according to the brightness of the external light measured by the photometric device 44 through the viewing window 6 and the sensitivity of the image sensor 46 when the release button 5 is pressed by the user. To do. When the CPU 40 determines that the flash light emission unit 4 is to emit light, the CPU 40 outputs a light emission signal to the light emission control circuit 48, and a flash discharge tube (not shown) of the flash light emission unit 4 is connected from the light emission control circuit 48 via the trigger lead wire 49. Make it emit light. The light beam emitted from the flash light emitting unit 4 is guided to the annular light guide member 10a, changed into a predetermined light beam, and then emitted from the emission surface 14a.

  Next, with reference to FIG.7 and FIG.8, operation | movement of the light beam guide | induced to the annular light guide member 10a is demonstrated. 7 and 8 show a part of the annular light guide member in a cutout form for easy viewing. This is because ray tracing continues if the notch is eliminated. FIG. 7 is a diagram for explaining how the light beam behaves depending on the incident position of the light beam guided from the flash light emitting unit 4 when the radial width of the light guide member is wide. FIG. 7A to FIG. 7C are obtained by sequentially changing the position where the light beam is incident from the side closer to the photographing optical axis to the side farther from the photographing optical axis.

  FIG. 7A shows a state where a light beam is incident from a position close to the inner peripheral portion of the annular light guide member 10a. As shown in FIG. 7A, the light beam incident on this position is most likely to escape from the outer periphery of the annular light guide member 10a because the angle with respect to the normal line standing on the outer peripheral surface is small and it is difficult to satisfy the total reflection condition. In FIG. 7A, the side surface of the annular portion is not a reflecting surface. As a result, there are many components that are injected from the outer periphery. In particular, when the width of the ring-shaped light guide member 10a is wide, the position that first hits the outer peripheral portion becomes a position away from the incident portion, and this tendency becomes strong.

  FIG. 7B shows a state in which the light beam is incident from a position close to the center of the incident surface of the annular light guide member 10a. The light beam incident on this position has many components that are guided while being totally reflected inside the light guide member, and there are few components that escape from the outer periphery of the light guide member. The light beam being guided has a small component passing through the vicinity of the inner periphery of the light guide member, and this also indicates that there is less light emitted from the vicinity of the inner periphery of the light guide.

  FIG. 7C shows a state in which the light beam is incident from the position closest to the outer periphery of the annular light guide member 10a. As shown in FIG. 7C, the light beam incident at this position can be guided efficiently because there is no component that escapes outward from the outer periphery of the annular light guide member 10a. Moreover, it turns out that it is guide | induced along the outer peripheral part of an annular | circular shaped light guide part as the characteristic of the light guide in this case. Also in this case, the light flux passing through the vicinity of the inner periphery of the annular light guide is small, and most of the light incident from the position closest to the outer periphery is irradiated from the vicinity of the outer periphery of the light guide member 10a. is expected.

  Thus, when the width of the annular light guide member 10a is wide, there is a component that escapes from the outer peripheral portion of the light guide member depending on the incident position on the ring-shaped light guide member 10a. Moreover, there are few components near the inner peripheral part of the ring-shaped light guide member 10a, and there is a tendency that components near the outer peripheral part are increased. From this, when the width of the annular light guide member is wide, it seems that the area of the emission part is large at first glance, which is desirable as a form of this type of light emitting part. Cannot be used effectively. In addition, uniform light emission is not always possible in all regions of the light emitting surface.

  In Example 1, in order to solve this problem, the light flux leaking from the outer peripheral portion of the annular light guide member 10a is minimized, and a uniform light flux is emitted from the entire surface of the wide annular light guide member 10a. .

  Next, a light guide state when the width of the annular light guide member 10a is changed will be described with reference to FIGS. Note that, as described with reference to FIG. 7, when the light beam is incident on the annular light guide member 10 a from the position close to the inner peripheral portion, it is most likely to escape to the outer peripheral portion. For this reason, the light guide members having different widths shown in FIG. 8 are also compared in the case where the light beam is incident from the vicinity of the inner periphery, which is the most severe condition.

  8A shows the widest annular light guide member 10a, FIG. 8C shows the narrowest annular light guide member 10a, and FIG. 8B shows an intermediate width circle. An annular light guide member 10a is shown. In FIG. 8A, similarly to FIG. 7A, when the light beam is incident from the vicinity of the inner peripheral portion of the wide annular light guide member 10a, the light beam easily escapes from the outer peripheral portion. In the annular light guide member 10a having an intermediate width shown in FIG. 8B, the light flux from the outer peripheral portion is extremely reduced, but the light beam is still extracted from the outer peripheral portion. In the annular light guide member 10a having the narrowest width shown in FIG. 8C, the light beam does not escape to the outer peripheral portion, and the light beam can be efficiently guided to the annular light guide portion. As can be seen from the comparison between FIG. 8 (a) to FIG. 8 (c), even if the light distribution immediately after the light beam is incident is the same, the incident light is reflected on the outer peripheral surface due to the difference in inner and outer diameters. This is due to the change in the angle formed with respect to the standing normal.

  With reference to FIG. 9, it will be described that light rays are more easily removed from the outer peripheral portion due to a change in the width of the light guide member. FIG. 9 is a cross-sectional view in which the annular light guide members 10a having different widths are overlapped, and how the reflection angle of a light beam horizontally incident on the left side from the point D on the incident surface as a representative light beam changes. It is shown. In the figure, A is a common inner peripheral surface of a narrow annular light guide member and a wide annular light guide member, B is an outer peripheral surface of a narrow annular light guide member, and C is a wide circle. It is an outer peripheral surface of an annular light guide member. D is the base point of the light beam incident on the annular light guide member, E is the intersection point of the horizontal light beam emitted from the base point D and the outer peripheral surface B of the narrow annular light guide member, and F is on the intersection point E. The angle between the horizontal ray DE and the normal F is α. G is the intersection of the horizontal light beam emitted from the base point D and the outer circumferential surface C of the wide annular light guide member, and H is a normal line standing on the intersection point G. The horizontal light beam DG and the normal line H Let β be the angle formed by.

  As shown in the figure, the angle α between the light beam incident in the horizontal direction from the base point and the normal line standing at the point E of the narrow annular light guide member is the same as the point G of the wide annular light guide member. It becomes larger than the angle β formed with the normal H set in Therefore, even when the light beam is incident under the same conditions, the angle α is large when the width of the light guide portion 14b is narrow, that is, the total reflection condition is easily satisfied, and the angle β is small when the width of the light guide portion 14b is wide. It can be seen that the total reflection condition tends to be difficult to satisfy. In FIG. 9, a horizontal light beam with respect to the base point D is taken as a representative light beam, but the same tendency applies to other angle components.

  As described above, the width of the annular light guide member 10a and the drop of light from the outer peripheral portion of the annular light guide member 10a have a close relationship, and the narrower the width of the annular light guide member 10a, the closer to the intersection of the outer peripheral portions. The angle with the raised normal is increased. When the light beam is guided through the annular light guide member 10a, the angle can be more easily reflected as the angle increases, which is advantageous in configuring the annular light guide member 10a. The optimum width of the annular light guide member 10a differs depending on the refractive index of the optical material and the angular distribution before entering the light guide member. However, a narrower width of the annular light guide member 10a qualitatively is more convenient for guiding the light beam using total reflection.

  As described above, it is effective to reduce the width of the annular light guide member 10a as much as possible in order to efficiently guide the annular light guide member 10a so that light does not leak from the outer peripheral portion. However, on the other hand, in close-up photography, the light-emitting part that can emit light uniformly from the whole light-emitting area has a shadow that allows light to rotate around the entire subject rather than the narrow and thin light-emitting part. It is also true that it is effective in softening.

  In order to satisfy these two requirements at the same time, this embodiment is similar to an optical member having a plurality of narrow light guide portions 14b by forming a plurality of concentric grooves 14c in an annular light guide member 10a. Has a special effect. As shown in FIGS. 1 and 4, the exit surface 4a side is formed of an annular plane, and a groove 14c having a cross-sectional shape as shown in FIG.

  As shown in FIG. 1, the light beam emitted from the flash light emitting unit 4 is reflected by the reflecting surface 17 b and guided in the counterclockwise direction to the annular part 11, as indicated by the arrow in the drawing, and the flash light emission. The light beam is guided directly downward from the portion 4 and separated into a light beam guided clockwise to the annular portion 11. This is a shape effective for efficiently guiding the light beam guided from the exit surface because the light emitting portion of the flash light emitting portion 4 is longer than the lateral width of the light receiving portion 15. In this way, the light beam emitted from the flash light emitting unit 4 is guided to the annular portion 11 through the light receiving unit 15.

  Here, in this embodiment, as shown in FIG. 5, slit-like grooves 14c are formed concentrically. The groove 14c prevents the light flux from being mixed in the light guide portion 14b adjacent to the light guide portion 14b. The side surface constituted by the groove 14c is configured to function as a total reflection surface. For this reason, it is desirable that the depth of the groove 14c is deeper, that is, the thinner the thickness connecting the light guide portions 14b is, the thinner.

  Further, it is desirable that the radial width of the groove 14c is narrow. This is because increasing the width of the groove 14c leads to a reduction in the area of the light guide portion 14b. As shown in FIG. 5, it is effective to narrow the width of the groove 14c as much as possible, that is, to narrow the width of the groove 14c to the molding limit of the resin material.

  In the present embodiment, the rear surface side of the light guide portion 14b is constituted by a rear surface 14d inclined in the optical axis direction of the photographing lens 3a. This is because, as shown in FIG. 3, the annular light guide member 10a is attached to the base portion of the taking lens barrel portion 3, that is, the exterior surface of the camera. There is a distance from the annular light guide member 10a to the tip of the taking lens barrel 3, and when shooting at an extremely close distance, depending on the amount of protrusion of the taking lens 3a, a sufficient amount of light flux goes around the center of the optical axis. There is a concern that it will not reach all over. In this embodiment, in order to minimize the light vignetting at the lens barrel at this close distance, the emission direction of the light beam is regulated so that the light beam emitted from the annular light guide member 10a is inclined toward the lens optical axis side. is doing. The inclined surface 14d in FIG. 5 has this shape, and the emitted light beam is intentionally directed inside by inclining the shape of the back surface side of the light guide portion toward the optical axis. As a result, it is possible to perform illumination with little lens barrel vignetting even on an extremely close subject.

  Returning to FIGS. 1 and 2, the second position is a position used for non-close-up photography, and is a position where the light receiving unit 15 is displaced from the flash light emitting unit 4 and exposes the flash light emitting unit 4. This arrangement is realized by rotating the annular light guide member 10a in the right direction around the lens barrel portion 3 from the position shown in FIG. By this operation, the light beam emitted from the flash light emitting unit 4 emits normal light without being guided to the annular light guide member 10a.

  Hereinafter, non-proximity imaging using the second position will be described. The operation mode of the camera 1 a is set to “strobe auto mode” by the mode changeover switch 42. Whether or not the flash button 4 is caused to emit light according to the brightness of the external light measured by the photometry device 44 through the viewing window 6 and the sensitivity of the image sensor 46 when the release button 5 is pressed by the user. Is determined by the CPU 40. When the CPU 40 determines that the flash light emitting unit 4 is caused to emit light, the CPU 40 outputs a light emission signal to the light emission control circuit 48, and a flash discharge tube (not shown) of the light emission control circuit 48 is connected from the light emission control circuit 48 via the trigger lead wire 49. Make it emit light.

  In the first embodiment, each light guide portion 14b is connected by a thin portion and the exit surface 14a is configured to be a flat surface. However, the present invention is not necessarily limited to this shape, and the minimum necessary portion is connected by the thin portion. It is good. With this configuration, the mixing of light rays between the light guide portions is further reduced, and the light flux can be uniformly guided.

  10 to 12 show a compact digital camera (imaging device) 1b according to the second embodiment. In addition, the camera which can mount the illuminating device of a present Example is not limited to the camera 1b shown in FIG.10 and FIG.11, Other cameras (Single-lens reflex camera, a video camera, etc.) may be used. 10 and 11 are front views of the camera 1b. The camera 1b includes a camera body 2, a photographing lens barrel portion 3, a flash light emitting portion 4, a release button 5 (not shown), a viewing window 6, a viewing window 7, an annular light guide member 10b, and a reflecting member (not shown). ), An intermediate member 50, a strap (connection member) 52, and a connection portion 54.

  The intermediate member 50 optically connects the flash light emitting unit 4 and the annular light guide member 10b. The strap 52 is connected to the connection portion 54 of the camera body 2, and an intermediate member 50 is attached to the tip portion to prevent inadvertent loss.

  The annular light guide member 10b is provided around the photographing lens barrel 3 on the front surface 2a of the camera body 2, and is used for close-up photography (macro photography). The annular light guide member 10b converts the light emission region from the flash light emitting unit 4 into an annular region (an emission surface 18a described later). The annular light guide member 10b is an optical member formed of a transparent body, and is formed of an optical organic polymer material with high transmittance such as polymethyl methacrylate (PMMA). The annular light guide member 10b of this embodiment is not cut and does not rotate.

  FIG. 12 is a cross-sectional view of the annular light guide member 10b. The annular light guide member 10b has an exit surface 18a, a plurality (five in this embodiment) of light guide portions 18b, grooves 18c, a back surface 18d, side surfaces 18e, and wall surfaces 18f.

  The exit surface 18a is a plane on which the light guided from the flash light emitting unit 4 is emitted. The plurality of light guides 18b are arranged concentrically around the taking lens barrel 3, and each guides light from the flash light emitting unit 4 along the concentric circles by total internal reflection, and has an annular shape. The groove 18c separates the light guide 18b. The light guide 18b and the groove 18c are formed concentrically with respect to the center of the hollow portion of the annular light guide member 10b. The reflecting plate (not shown) has a function of reflecting the light beam emitted to the side opposite to the exit surface 18a of the annular light guide member 10b and returning it to the annular light guide member 10b again. The outermost diameter is equal to or greater than the diameter. The diameter of the hollow part of the reflecting plate is the same as the diameter of the hollow part of the annular light guide member 10b, and the taking lens barrel part 3 is inserted into the hollow part of the reflecting plate. The back surface 18d is configured by a plane or a curved surface that is inclined in the optical axis direction of the photographing lens 3a. The side surface 18e may be configured as a reflective surface, but is configured as a transmission surface in the present embodiment. The wall surface 18f is an inclined surface that forms the groove 18c.

  Hereinafter, the close-up shooting will be described. At the time of close-up photography, as shown in FIG. 10, the intermediate member 50 connects the flash light emitting unit 4 and the annular light guide member 10b. The control system in this case corresponds to a control system without the rotation mechanism 30 shown in FIG.

  The operation mode of the camera 1 b is set to the “close-up shooting mode” by the mode switch 42. The intermediate member 50 is attached to the position shown in FIG. 10, whereby the light beam emitted from the flash light emitting unit 4 can be converted into a predetermined light beam and emitted from the annular light guide member 10 b. Further, depending on the setting of the “close-up shooting mode”, the shooting lens barrel unit 3 places the shooting lens 3a in a macro mode position suitable for close-up shooting. The CPU 40 determines whether or not the flash button 4 is caused to emit light according to the brightness of the external light measured by the photometric device 44 through the viewing window 6 and the sensitivity of the image sensor 46 when the release button 5 is pressed by the user. To do. When the CPU 40 determines that the flash light emission unit 4 is to emit light, the CPU 40 outputs a light emission signal to the light emission control circuit 48, and a flash discharge tube (not shown) of the flash light emission unit 4 is connected from the light emission control circuit 48 via the trigger lead wire 49. Make it emit light. The light beam emitted from the flash light emitting unit 4 is guided to the annular light guide member 10b through the intermediate member 50 and changed to a predetermined light beam, and then emitted from the emission surface 18a.

  The annular light guide member 10b of the present embodiment has a light emitting portion 18b having a wall surface 18f, although the exit surface 18a is formed of an annular flat surface as in the first embodiment. It is different. Such a structure is effective for providing directivity to the luminous flux of each of the divided light guide portions 18b. By restricting the inclination of the wall surface 18f forming the light guide portion 18b, the radial irradiation angle range at the time of emission from the annular light guide portion 18b can be controlled to some extent. That is, by making the shape of each light guide portion 18b to be divergent as it approaches the exit surface, it is possible to qualitatively narrow the radial irradiation angle range and efficiently irradiate the required irradiation range. it can. This utilizes the fact that the component totally reflected by the inclined wall surface 18f of the light guide is converted to an angle close to the photographing optical axis after reflection. This shape is also effective when processing the annular light guide member 10b. Formability of the optical resin material can be improved by providing an inclination to the wall surface 18f of each light guide portion 18b.

  Also in the present embodiment, the light guide portion 18b has a back surface 18d that is inclined in the optical axis direction of the photographing lens 3a. This is because, similarly to the first embodiment, the influence of the light vignetting on the lens barrel portion at a close distance is minimized by causing the emitted light beam to go around the lens optical axis. In this embodiment, the surfaces on both sides of the side surface forming the groove 18c are inclined, but the inclined side surface may be only one side.

  FIG. 11 is a position used for non-close-up photography, and is a position where the intermediate member 50 is displaced from the flash light emitting unit 4 and exposes the flash light emitting unit 4. This arrangement is realized by the user manually moving the intermediate member 50 from the position shown in FIG. By this operation, the light beam emitted from the flash light emitting unit 4 emits normal light without being guided to the annular light guide member 10b.

  Hereinafter, non-proximity imaging will be described. The operation mode of the camera 1b is set to “strobe auto mode” by the mode changeover switch. Whether or not the flash button 4 is caused to emit light according to the brightness of the external light measured by the photometry device 44 through the viewing window 6 and the sensitivity of the image sensor 46 when the release button 5 is pressed by the user. Is determined by the CPU 40. When the CPU 40 determines that the flash light emitting unit 4 is caused to emit light, the CPU 40 outputs a light emission signal to the light emission control circuit 48, and a flash discharge tube (not shown) of the light emission control circuit 48 is connected from the light emission control circuit 48 via the trigger lead wire 49. Make it emit light.

  The third embodiment is a modification of the first and second embodiments, and only the shape of the grooves of the annular light guide members 10a and 10b is deformed. Since other configurations are the same, description thereof is omitted.

  The annular light guide member 10c is provided around the photographing lens barrel 3 on the front surface 2a of the camera body 2, and is used for close-up photography (macro photography). The annular light guide member 10 c converts the light emission area from the flash light emitting unit 4 into an annular area (an emission surface 19 a described later). The annular light guide member 10c is an optical member formed of a transparent body, and is formed of an optical organic polymer material with high transmittance such as polymethyl methacrylate (PMMA). The annular light guide member 10c of this embodiment is not cut and does not rotate.

  FIG. 13 is a cross-sectional view of the annular light guide member 10c. The annular light guide member 10c has an exit surface 19a, a light guide portion 19b, a groove 19c, and a back surface 19d. The emission surface 19a is a plane on which the light guided from the flash light emitting unit 4 is emitted, and is divided into five by a plurality of (four in this embodiment) grooves 19c. The plurality of light guides 19b are concentrically arranged around the photographing lens barrel 3, and each guides the light from the flash light emitting unit 4 along the concentric circles by total internal reflection, and has an annular shape. Similarly, the plurality of light guides 19b are divided into five by grooves 19c. The groove 19c separates the light guide portion 19b. The light guide portion 19b and the groove 19c are formed concentrically with respect to the center of the hollow portion of the annular light guide member 10c, and are exposed on the surface of the camera body. The reflecting plate (not shown) has a function of reflecting the light beam emitted to the side opposite to the exit surface 19a of the annular light guide member 10c and returning it again to the annular light guide member 10c. The outermost diameter is equal to or greater than the diameter. The diameter of the hollow part of the reflecting plate is the same as the diameter of the hollow part of the annular light guide member 10c, and the taking lens barrel part 3 is inserted into the hollow part of the reflecting plate. The back surface 19d is a plane parallel to the exit surface 19a and is not divided. As shown in FIG. 13, even if the groove 19c is provided on the exit surface 19a side of the annular light guide member 10c, it can be separated into a plurality of thin light guides as in the first and second embodiments, and is almost equivalent. An effect can be obtained.

  The fourth embodiment is a modification of the first and second embodiments, and only the shape of the grooves of the annular light guide members 10a and 10b is deformed. Since other configurations are the same, description thereof is omitted.

  The annular light guide member 10d is provided around the photographing lens barrel 3 on the front surface 2a of the camera body 2, and is used for close-up photography (macro photography). The annular light guide member 10d converts the light emission region from the flash light emitting unit 4 into an annular region (an emission surface 20a described later). The annular light guide member 10d is an optical member formed of a transparent body, and is formed of an optical organic polymer material with high transmittance such as polymethyl methacrylate (PMMA). The annular light guide member 10d of this embodiment is not notched and does not rotate.

FIG. 14 is a cross-sectional view of the annular light guide member 10d. An annular guide member 10d is an exit surface 20a, the light guide portion 20b, grooves 20c ₁ and 20c _2, having a back 20d. Exit surface 20a is a plane light guided from the flash emitting unit 4 is emitted, it is divided into a plurality (in this example four) to five by the grooves 20c ₁ of. The plurality of light guide portions 20b are concentrically arranged around the photographing lens barrel portion 3, and each guides the light from the flash light emitting portion 4 along the concentric circles by total internal reflection, and has an annular shape. A plurality of light guide portion 20b, likewise, is divided into five by the grooves 20c _2. The grooves 20c ₁ and 20c ₂ separate the light guide unit 20b. The light guide portion 20b and the groove 20c ₁ and 20c ₂ is formed concentrically with respect to the center of the hollow portion of the annular guide member 10d, exposed on the surface of the camera body. The reflector (not shown) has a function of reflecting the light beam emitted to the side opposite to the exit surface 20a of the annular light guide member 10d and returning it to the annular light guide member 10d again. The outermost diameter is equal to or greater than the diameter. The diameter of the hollow portion of the reflecting plate is the same as the diameter of the hollow portion of the annular light guide member 10d, and the taking lens barrel portion 3 is inserted into the hollow portion of the reflecting plate. Back 20d is a parallel plane and exit plane 20a, is divided into five by the grooves 20c _2. As shown in FIG. 14, similarly to the annular guide member 10d be both a groove 20c ₁ and 20c ₂ of the exit surface 20a side and the back 20d side of the first and second embodiments, a plurality of thin light guide portion It is possible to obtain a substantially equivalent effect.

In particular, as in this embodiment, the case of forming the grooves 20c ₁ and 20c ₂ on either side of the exit surface 20a back 20d is the width of the groove because it is possible to set shallower the depth of each groove There is a high possibility of narrowing. Therefore, it becomes possible to reduce the volume of the grooves 20c ₁ and 20c ₂ does not function as a light guide portion 20b, it is possible to construct a more efficient lighting system.

1 is a front view of a camera (imaging device) according to Embodiment 1. FIG. 1 is a front view of a camera according to Embodiment 1. FIG. It is a perspective view of the camera shown in FIG. It is a fragmentary perspective view of the annular light guide member shown in FIG. It is a fragmentary sectional view of the annular light guide member shown in FIG. It is a block diagram of the control system of the camera shown in FIG. It is a figure which shows the relationship between the light beam incident position of an annular light guide member, and light beam leakage. It is a figure explaining the relationship between the change of the width | variety of the annular light guide member shown in FIG. 1, and the behavior intention of a light ray. It is a figure for demonstrating that a light ray will fall easily from an outer peripheral part by the width change of the annular light guide member shown in FIG. 6 is a front view of a camera (imaging device) according to Embodiment 2. FIG. 6 is a front view of a camera according to Embodiment 2. FIG. It is a fragmentary sectional view of the annular light guide member shown in FIG. 6 is a partial cross-sectional view of an annular light guide member of Example 3. FIG. It is a fragmentary sectional view of the annular light guide member of Example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Camera 2 Camera body 3 Shooting lens barrel part 3a Shooting lens 4 Flash light emission part 10a, 10b, 10c, 10d Toroidal light guide members 14b, 18b, 19b, 20b Light guide parts 14c, 18c, 19c, 20c ₁ 20c ₂ grooves 30 Rotating mechanism 40 Central processing unit (CPU)
50 Intermediate member 52 Strap (connection member)

Claims (8)

A lighting device comprising: a flash light emitting unit; and an annular light guide member that converts an emission region of light from the flash light emitting unit into an annular region;
A taking lens barrel that houses the taking lens;
An imaging device having
The annular light guide member is:
A plurality of light guides arranged concentrically around the taking lens barrel, each guiding light from the flash light emitting part along the concentric circles, and having an annular shape;
An imaging apparatus comprising: a plurality of grooves arranged concentrically with the plurality of light guides and separating the plurality of light guides.   The imaging apparatus according to claim 1, wherein a width of the groove in a radial direction of the concentric circle is narrower than a width of each light guide portion in the radial direction of the concentric circle.   The groove is formed on at least one of an emission surface on which the annular light guide member emits light from the flash light emitting portion and a back surface on the opposite side of the emission surface. Item 2. The imaging device according to Item 1.   The imaging apparatus according to claim 1, wherein when the annular light guide member is cut along a cross section including a diameter of the concentric circle, the groove has a shape that spreads outward. The annular light guide member is:
An emission surface that is a plane that emits light from the flash light emitting unit;
A back surface opposite to the exit surface;
Have
The imaging apparatus according to claim 1, wherein the back surface is a flat surface parallel to the exit surface, or an inclined surface inclined toward the optical axis center side of the photographing lens. The annular light guide member is:
An annular portion for emitting light from the flash light emitting portion;
A light receiving portion connected to the annular portion, receiving light from the flash light emitting portion and guiding the light to the annular portion;
Have
The imaging device
A rotating mechanism that rotates the annular light guide member between a first position where the light receiving portion receives the light from the flash light emitting portion and a second position where the light receiving portion is separated from the flash light emitting portion. The imaging apparatus according to claim 1, further comprising: The illumination device further includes an intermediate member that receives light from the flash light emitting unit and guides the light to the annular light guide member,
The imaging device
The imaging apparatus according to claim 1, further comprising a connection member that connects the intermediate member to a camera body to which the photographing lens barrel portion is attached. An illumination device having a light source and an annular light guide member that converts an emission region of light from the light source into an annular region,
The annular light guide member is:
A plurality of light guides arranged concentrically, each guiding light from the light source along the concentric circles;
An illuminating device comprising: a plurality of grooves arranged concentrically with the plurality of light guides, and separating the plurality of light guides.